OTM FREQUENCY AGILE 750MHz F.C.C. COMPATIBLE TELEVISION MODULATOR INSTRUCTION MANUAL

Transcription

1 OTM-4000 FREQUENCY AGILE 750MHz F.C.C. COMPATIBLE TELEVISION MODULATOR INSTRUCTION MANUAL Phone: (209) (800) Fax: (209) REV B 8/21/01

2 OTM-4000 FREQUENCY AGILE 750MHz F.C.C. COMPATIBLE TELEVISION MODULATOR 1) INTRODUCTION The Olson Technology OTM-4000 is a frequency agile, F.C.C. compatible television modulator. This microprocessor-controlled unit is capable of operation on any frequency from 48MHz to 750MHz and output frequency selection is possible in MHz increments. Output frequencies may be selected in MHz or by channel designation. Standard, HRC, IRC, or EIA channel plans may be specified. FCC offsets of +12.5KHz and +25KHz are automatically provided depending on the plan and/or channel chosen. An RF output level of +60dBmV (minimum) is possible over the operating frequency range of the OTM SAW filtering and Olson Technology system design factors insure an out-of-band carrier-to-noise ratio greater than 80dB. This allows unlimited numbers of these units to be combined. The OTM-4000 has many advanced features including a menu/button control system, front panel display of channel and channel ID text, a manual or loss-of-video controlled auxiliary I.F. input with AGC, selectable video AGC, external audio subcarrier input, configurable audio input, dual IF loops, BTSC compatibility, optional remote control, and more. 2) LOCAL CONTROL OF THE OTM-4000 A.) FRONT PANEL ADJUSTMENTS: Video and audio modulation levels, video-to-audio carrier ratio, and the RF output level are adjustable by means of slotted controls accessible through the front panel. There is also a control for the LCD panel contrast which should be adjusted for proper viewing once the unit is installed. See section 4 of this manual for more information on these adjustments. B.) FRONT PANEL MENU ITEM CONTROLS: Most features of the OTM-4000 are configurable from the front panel by means of the menu/button system which includes an LCD panel and 5 buttons. The LCD panel displays the menu(s) and the currently-selected configuration or value. The UP, DOWN, LEFT, and RIGHT buttons are used to move between menus, to select configurations, and to change values. All items except tuning mode and channel number/frequency will instantly change to match the display. A new tuning mode or channel/frequency takes effect only when you press the ENTER button. To make other changes permanent, press the ENTER button. Note that when changing the output frequency, the unit s digital synthesizer may become unlocked momentarily resulting in operation on an undesired frequency until it re-locks. The OTM-4000 will turn it s RF output off anytime the unit is in an unlocked state, thus preventing unwanted interference when changing channels. As illustrated on page 5 below, there are two menu trees; the main menu tree (on the left) and the sub-menu tree (on the right). The arrows indicate which buttons to press to move around the menus. Review each menu and the information below to become familiar with the various functions REV B Page 2

3 C.) CHANGING MENU ITEMS: To change a function or value, select the menu containing the item to change using the UP, DOWN, RIGHT, and LEFT buttons. After selecting the correct menu, press the RIGHT button to change a menu item. If part or all of the bottom row starts flashing, you can change that item. If the entire bottom row flashes (most items), press the UP or DOWN button to change it. These buttons have auto-repeat. For tuning or channel ID (NAME) values, only one character in the bottom row will flash. The LEFT and RIGHT buttons select the position to change and the UP and DOWN buttons change the value. When you are through with the change (or if there is no change), pressing the ENTER button will enable the displayed parameter or value, the change mode is exited, and the display will stop flashing. If you do not press the ENTER key, the parameter will return to the original value after a time-out of about 15 seconds. 3.) SOME MENU-SPECIFIC INFORMATION A.) Display of NAME and TUNING: B.) IF INPUT: This is the normal (default) display and is the menu shown as the top left menu on page 5 of this manual. You can not make any change from this menu. The NAME is programmable from the NAME menu and the tuning is programmable from the TUNING menu. The display will return to this default after about 30 seconds of button inactivity If the programmed TUNING MODE is CHAN, the display will be the channel number. If the programmed TUNING MODE is FREQ, the display will be the frequency in MHz. Note that if the TUNING MODE is changed from CHAN to FREQ, the LCD will display the frequency of the previously-selected channel. This indicates the preferred choice of the normal IF source. A rear panel input or an automatic transfer could switch to the AUX IF input. C.) CHANNEL PLAN: D.) NAME: The CHANNEL PLAN determines the OTM-4000 output frequency for a selected channel number. Tables at the end of this manual list these values. Note that FCC offsets are automatically provided for the STD and EIA channel plans and that an offset is applied to all channels in the IRC plan. The HRC channel plan provides no offsets. This menu allows you to program the NAME that appears at the top of the normal (default) display. Upper case and lower case letters as well as numbers and various symbols are available for use. E.) COMMAND MODE, BAUD RATE, and ADDRESS: These functions are only used when the OTM-4000 is configured with the optional remote control feature REV B Page 3

4 NOTE: Arrows indicate which keys to press to move through menus REV B Page 4

5 4.) FRONT PANEL CONTROLS AND INDICATORS REMOTE UNLOCKED When an OTM-4000 is equipped with the optional remote control feature, this LED when on, indicates that the OTM-4000 is in the remote control mode. This LED when on, indicates that one of the digital synthesizers is not locked. This condition will result in shutdown of the RF output as long as the condition exists. Note that this LED will usually flash on momentarily when changing a channel or frequency. This momentary shutdown of the output prevents undesired interference to other channels if the OTM-4000 is connected to a system or network when it s channel is changed. VIDEO LEVEL VIDEO O/M This control adjusts the video depth-of-modulation. Choose a bright scene (commercials are usually excellent) and set it carefully while observing the VIDEO O/M LED. This control should be advanced to a point JUST SHORT of where the VIDEO O/M LED flashes-on. This LED, when on, indicates a depth-of-modulation greater than 87-1/2%. It should never be on continuously but might be on for short periods during bright scenes. See VIDEO LEVEL above. This LED will stay on for several seconds when power is first applied to the OTM AUDIO LEVEL AUDIO O/M A/V This control adjusts the audio deviation of the OTM Choose program material that is of high average volume when setting this control and adjust it so the AUDIO O/M LED just blinks-on during program audio level peaks. This LED, when on, indicates that the peak deviation of the OTM-4000 is at ±25KHz. It should only flash-on occasionally during normal operation. See AUDIO LEVEL, above. This control adjusts the aural carrier level relative to the video carrier level. It is typically adjusted for an A/V ratio of 15-17dB. LEFT, RIGHT, UP, DOWN, ENTER CONTRAST AUX IF These buttons are used in selecting and changing menu items as displayed on the LCD panel. This control adjusts the LCD panel contrast. Adjust it for best display legibility when the OTM-4000 is placed in operation. This LED, when on, indicates that the current IF source is the AUX input at the rear panel REV B Page 5

6 LCD DISPLAY PANEL This displays menu and status information. OUTPUT RF LEVEL RF ON This control is used to set the RF output level. If the OTM-4000 is feeding a system or network with many channels, it is suggested that it be operated at an output level of +55dBmV minimum to prevent degradation of the C/N ratio of that channel. If lower output levels are required, place an in-line attenuator at the RF output. Note that the OTM-4000 may be capable of output levels greater than +60dBmV on some channels. The specifications for spurious performance, etc are based on a maximum operating level of +60dBmV. This unit may not meet it s full specification if operated at greater that +60dBmV out. This LED indicates the output RF status. 5.) REAR PANEL CONNECTIONS RF TEST RF OUT HOST IN NEXT OUT AUX IN VIDEO IF IN This output is approximately 20dB below the main RF output and may be used for monitoring or test. This RJ connector is only present when the optional remote control module is installed and it is the remote control input for the modulator. This RJ connector is only present when the optional remote control module is installed and it is used to connect a next modulator in a site with a group of remotely-controlled OTM-4000 s. This is the AUX IF input. This input is before the SAW IF section and normally expects an IF input level of +38 dbmv. It has AGC which will allow levels to vary as much as ±5dB while holding the RF output level constant. This input may be enabled by shorting the AUX SELECT terminals on the rear panel, by front panel control, by loss of video, or by (optional) remote control. This is the video IF input to the SAW filter / output converter section. The AUX IF switch is AF- TER this input. The video IF level at this point should be +38 dbmv. In normally-configured applications this input is usually connected to the VIDEO IF OUT connector. The OTM-4000 is shipped from the factory with this jumper in place REV B Page 6

7 AUDIO IF IN This is the aural IF input to the SAW filter / output converter section. The AUX IF switch is AFTER this input. The aural IF level at this point is relative to the video IF level as at the unit RF output. IE: If the A/V ratio at the output is 15dB, then the aural IF level at this point would be approximately 15 db below the video IF level at the VIDEO IF IN connector (approximately +23dBmV). In normally-configured applications this input is usually connected to the AUDIO IF OUT connector. The OTM-4000 is shipped from the factory with this jumper in place. AUDIO IF OUT This is the aural IF output from the IF modulator section. The aural IF level here is relative to the video IF level as at the unit RF output. IE: If the A/V ratio at the output is 15dB, then the aural IF level at this point would be approximately 15 db below the video IF level at the VIDEO IF IN connector (approximately +23dBmV). In normally-configured applications this output is usually connected to the AUDIO IF IN connector. The OTM-4000 is shipped from the factory with this jumper in place. VIDEO IF OUT VIDEO IN This is the video IF output from the IF modulator section. The video IF level here is +38dBmV. In normally-configured applications this output is usually connected to the VIDEO IF IN connector. The OTM-4000 is shipped from the factory with this jumper in place. 1 Volt P-P baseband video input to the OTM When VIDEO AGC is enabled, the modulation will remain constant for input level changes of ±3dB. AUX SELECT AUDIO IN When these two terminals are connected together, the AUX IF IN is enabled. This is a hard control and will override any other function that instructs the internal IF to be selected. The left terminal is chassis ground and the right terminal is grounded to activate the function. Baseband audio input to the OTM This input is configurable for 600Ω balanced or high impedance unbalanced applications. When configured for high impedance input, ground should be connected to the right-side terminal. To change from 600Ω to high-impedance input, disconnect the unit from AC power, remove the top cover and locate jumper JMP1 near the front left corner of the circuit board. Move the jumper from the position marked BAL to the position marked UNBAL. If it is desired to defeat the audio pre-emphasis for baseband BTSC input or other applications, locate the jumper marked JMP2 and move it from the position marked PRE-EMPH to the position marked BYPASS REV B Page 7

8 EXT SUB IN External aural subcarrier input. This input is selectable from the front panel or (optional) remote control. The input level (at 4.5 MHz for NTSC versions) should be +45dBmV (measured into 75Ω). The OTM-4000 has limiter circuitry to keep the aural carrier constant with small changes in the external subcarrier signal level. AC LINE POWER INPUT 5.) MISCELLANEOUS The OTM-4000 may be powered by 90 to 240 VAC and HZ and it draws about 30 Watts. A) When mounting the OTM-4000 in an equipment rack, it is best to leave a blank space above and below the unit to allow for adequate flow of cooling air. B.) This unit is equipped with a 0.5A slo-blo fuse which is located at the IEC power input module at the rear panel. For continued safety and to maintain proper performance of the unit, please replace only with an equivalent fuse REV B Page 8

9 OTM-4000 CHANNEL PLANS REV B Page 9

10 OTM-4000 CHANNEL PLANS (Continued) * NOTE: A-1 through A-8 reference designations on this chart do not apply to the EIA channel plan listings REV B Page 10

11 OTM-4000 CHANNEL PLANS (Continued) REV B Page 11